JPH0362453B2 - - Google Patents

Description

[Detailed description of the invention]

A. Field of Industrial Application The present invention relates to an emulsifying and dispersing agent for a lipophilic water-insoluble substance made of a specific modified polyvinyl alcohol (hereinafter polyvinyl alcohol will be abbreviated as PVA) having a hydrophobic group and a hydrophilic group. B. Prior Art When manufacturing cosmetics, agrochemical synthetic resins, adhesives, various binders, paints, cutting oils, etc., lipophilic water-insoluble substances are often emulsified and dispersed in an aqueous medium. In this case, low-molecular surfactants are generally used as emulsifying and dispersing agents. C. Problem to be solved by the invention Although it is possible to obtain a somewhat stable emulsion by appropriately selecting a low-molecular surfactant, the stability at low temperatures or when mechanical shearing force is applied is poor. etc., resulting in practical problems such as thickening gelation during winter storage, generation of coarse particles during transfer by pump, or application by spreader roll, and large fluctuations in viscosity. There are cases. Furthermore, although using a large amount of a low-molecular-weight surfactant may solve the above stability problems, the emulsion may have a strange odor or a large amount of the surfactant may be present in the resulting film. This poses a very serious problem in practical terms, such as the adhesive performance and water resistance of the film being significantly reduced. Furthermore, there are various problems such as the fact that only low viscosity emulsions can be obtained when low-molecular active agents are used, and the development of emulsifying and dispersing agents based on polymeric surfactants is awaited. PVA is a water-soluble polymeric substance and is used in various industrial applications because of its ability to form tough films. However, because it has only simple substituents of hydroxyl and acetate groups on the carbon skeleton of its main chain, it does not have sufficient surfactant ability, and there are many difficulties when using it as an emulsifying and dispersing agent. It goes along with that. D Means for Solving the Problems In view of the above-mentioned circumstances, the present inventors have conducted intensive research and found that lipophilic properties can be achieved by using a specific modified PVA having hydrophobic groups and hydrophilic groups as described below. The emulsified dispersion obtained by emulsifying and dispersing a water-insoluble substance in an aqueous medium is highly stable, has excellent storage properties, mechanical properties, etc., and also has excellent practical physical properties such as adhesive performance. This discovery led to the present invention. That is, the present invention provides (A) a vinyl ether having an alkyl group having 4 or more carbon atoms, (B) a monomer represented by the general formula (), In the above formula, R ₁ ; hydrogen or lower alkyl group R ₂ ; alkyl group R ₃ , R ₄ , R ₅ ; hydrogen or alkyl group M; hydrogen or one equivalent of cation (C) vinyl acetate; This is an emulsifying and dispersing agent that can emulsify and disperse a lipophilic water-insoluble substance in an aqueous medium made of modified PVA obtained by saponifying a copolymer contained as a polymerization component. In the modified PVA constituting the emulsifying dispersant of the present invention,
Vinyl ethers with alkyl groups having 4 or more carbon atoms used as component (A) include butyl vinyl ether, octyl vinyl ether, lauryl vinyl ether, etc., but vinyl ethers with branched alkyl groups such as isoamyl vinyl ether are more preferred. It is difficult to obtain emulsions with good stability using modified PVA using vinyl ethers having alkyl groups having 3 or less carbon atoms. As the above-mentioned component (A), a monomer having a branched alkyl group is more preferably used because it is more stable and can yield an emulsion having good practical properties such as water resistance and adhesive performance. The reason for this is not clear, but it is due to the fact that the ratio of methyl, methylene, and methine groups in the alkyl group is different between branched and straight-chain alkyl groups, and differences in crystal orientation, association, etc. It is thought that this may be the case. Furthermore, the monomer used as component (B) is represented by the following general formula (). Here, R ₁ is hydrogen or a lower alkyl group, usually hydrogen or a methyl group, and more preferably hydrogen, R ₂ is required to be an alkyl group, and R ₃ , R ₄ , and R ₅ are hydrogen Alternatively, R 3 is an alkyl group, but it is preferable that R ₃ be an alkyl group because the stability of the emulsion is greater. The reason is not clear, but it is due to the hydrophilic part within the molecule.

[Formula] The mutual steric positional relationship between the group and the -SO ₃ M group, the methylene skeleton of the main chain, the (A) component used as the hydrophobic side chain, etc.
This may be because R ₁ , R ₂ , R ₃ , R ₄ , R ₅ varies depending on the size of the groups, or during the process of copolymerizing and saponifying the monomers of formula () above, R ₁ , R ₂ , _R3 , _R4 , _R5
It is thought that the molecular structure of modified PVA changes depending on the size of the group and influences its surfactant ability. M is one equivalent of hydrogen or cation. The modified PVA constituting the emulsifying dispersant of the present invention can be obtained by saponifying a copolymer containing the above-mentioned components (A), (B), and (C) as essential components. Although the copolymerization ratio of component (A) contained in the copolymer varies depending on the number of carbon atoms, a range of 0.2 to 5 mol% is preferable among 0.05 to 10 mol%. The copolymerization ratio of component (B) contained in the copolymer varies depending on the copolymerization ratio of component (A), but it is 0.1 to 6 mol% among 0.05 to 8 mol%.
A range of is suitable. The modified PVA of the present invention is a saponified copolymer having the three components (A), (B), and (C) as essential components, but other copolymers may be used as long as the purpose of the present invention is not impaired. Ingredients such as methacrylamide, acrylamide,
There is no problem in using N-vinylpyrrolidone as a copolymerization component in addition to the above-mentioned three components (A), (B), and (C) as well as a saponified copolymer. There are no particular difficulties in producing the modified PVA of the present invention, and conventionally known polymerization methods and saponification methods can be applied. In other words, as a polymerization method, components (A), (B), and (C) are added to a polymerization system all at once, in parts, or continuously depending on their respective copolymerization reactivity ratios, and the A method of polymerization using a radical polymerization initiator such as 2,2'-azobisisobutyronitrile or benzoyl peroxide in a medium or in the presence of a lower alcohol such as methyl alcohol or ethyl alcohol can be applied. (A), (B) and
As a method for saponifying the copolymer containing component (C), many known methods used for saponifying polyvinyl acetate copolymers can be applied, but usually, in an alcohol solvent or a hydroalcoholic solvent, A suitable method is saponification using an alkali such as sodium alcoholate, caustic soda, or caustic potash. As alcohol, methyl alcohol,
Lower alcohols such as ethyl alcohol are particularly preferred. In addition, these alcohols contain 40% by weight
A solvent such as acetone, methyl acetate, ethyl acetate, benzene, etc. may be contained as long as it is below. There is no particular restriction on the degree of saponification of the modified PVA, and it may be completely saponified or partially saponified, but it is preferably 60 mol% or more. The degree of polymerization of the modified PVA of the present invention should be appropriately selected depending on its intended use, but is usually in the range of 100 to 3,000. The lipophilic water-insoluble substances to be emulsified and dispersed by the emulsifying dispersant of the present invention include, for example, lubricating oils such as spindle oil and gear oil, petroleum products such as paraffin wax, liquid paraffin, and asphalt, dioctyl sepacate, Subplastic agents such as dibutylphthalate, tar products such as creosote oil and coal tar, natural chemicals such as turpentine oil, tall oil, and rosin, oils and fats such as soybean oil and castor oil, benzene, toluene, and xylene. Aromatic hydrocarbons such as paraffins, halogenated hydrocarbons, ketones such as methyl n-amyl ketone and di-n-propyl ketone, ethers isocyanates such as xylylene diisocyanate and trimethylolpropane-tolylene diisocyanate adduct. higher fatty acids such as caproic acid and linoleic acid, higher alcohols such as oleyl alcohol and cetyl alcohol, polyethylene, polypropylene, polyvinyl chloride, polyester, polyvinyl acetate ester, ethylene-vinyl acetate ester copolymer, and its polymers. Examples include, but are not limited to, chemical compounds, various synthetic rubbers, etc.
It can be widely used for emulsifying and dispersing lipophilic water-insoluble substances. For emulsification and dispersion, conventionally known methods are employed. For example, general fluid stirrers, high-speed rotation, strong shear type stirring and dispersion machines, colloid mills, pressure nozzle emulsifiers, screw extruders, ultrasonic emulsifiers, mechanical vibration stirrers, stirrers that use electrostatic fields, etc. This can be done using the method you use. There are no particular restrictions on the method for adding the emulsifying dispersant, and the emulsifying dispersing agent may be mixed with water and added to the lipophilic water-insoluble substance all at once, sequentially, or even continuously. There is a method in which an emulsifying dispersant is blended with a lipophilic water-insoluble substance and then mixed with water, and a method in which all three are added at the same time. There is no particular restriction on the blending ratio of modified PVA as an emulsifying dispersant, but it is preferably blended in an amount of 1 to 30% by weight based on the lipophilic water-insoluble substance described above. Other types of additives may be used in carrying out the process of the invention, such as fatty acid soda soaps, alkyl ether sulfates, benzyltrimethylammonium chloride, ionic surfactants such as dioctyl sodium sulfosuccinate, polyoxyethylene oleyl ether, sorbitan monostearer, etc. rate oxyethylene oxypropylene block polymer,
Nonionic surfactants such as glycerol monostearate, water-soluble polymers such as sodium polyacrylate, polyacrylamide, unmodified or modified PVA, cellulose derivatives, and other antifoaming agents, antifungal agents, and antirust agents. There is no problem in adding and using known additives such as additives as long as the purpose of the present invention is not impaired. E. Effects and Effects of the Invention The emulsified dispersion of lipophilic water-insoluble substances obtained in this way is highly stable, and when used with emulsions of synthetic resins, excellent coatings can be obtained. It has industrial significance and greatly contributes to the development of industry. EXAMPLES The present invention will be explained in more detail with reference to examples below, but the present invention is not limited thereto. Note that parts in the examples are based on weight unless otherwise specified. Example 1, Comparative Examples 1 to 4 Modified PVA containing the various copolymer components listed in Table 1 was used to examine its emulsifying performance as follows. That is, after dissolving 5 parts of modified PVA in 500 parts of water, 300 parts of machine oil was gradually added to the mixture while stirring with a homomixer at 25°C to obtain an emulsion.
The emulsion was immediately placed in a lidded container with a radius of 3 cm and a height of 50 cm, and allowed to stand at 25°C, and the results were expressed as a percentage of the total height of the emulsified layer. As is clear from Example 1, the emulsifying and dispersing agent of the present invention provides a stable emulsion, and
Even after several days had passed, there was no separation of the emulsified layer and the aqueous layer. In Comparative Example 1, which used modified PVA containing only component (A) and no component (B) as a copolymerization component, the modified PVA did not dissolve in water and it was not possible to conduct an emulsification performance test. Comparative example 2 using modified PVA that contains only component (B) and no component (A) as a copolymerization component, unmodified PVA that does not contain both components (A) and (B)
In Comparative Example 3 using PVA, and Comparative Example 4 using modified PVA containing ethyl vinyl ether, which is a vinyl ether of an alkyl group with 2 carbon atoms, as component (A), the emulsion temporarily became emulsified, but 2 to 5 The emulsification was destroyed within days and the stability was poor.

[Table] Example 2, Comparative Examples 5 to 8 Polyisomer containing a small amount of 3,5 di-t-butyl-4-hydroxytoluene as an antiaging agent was prepared using an open kneader with a capacity of 60 c.c. Brene rubber (cis 1,4 content 98%, intrinsic viscosity at 30℃ in toluene
3.3 dl/g) was kneaded at 90°C for 15 minutes, and then a mixture of 5 g of various modified PVA shown in Table 2 and 5 g of water was added little by little and kneaded to obtain a white kneaded product. Further kneading was continued and when 5g of water was added, the mixture was removed from the kneader and 50g
The mixture was poured into water and stirred for subsequent testing. In Example 2, a clean emulsion without coarse particles was obtained, and the low temperature stability was also good. In Comparative Examples 5 to 7, in which PVA containing one or both of components (A) and (B) was used as a copolymerization component, a good emulsion was not obtained due to many coarse particles. Furthermore, when 10 times the amount of polyoxyethylene nonyl phenyl ether was added to unmodified PVA and emulsification was carried out in the same manner, a good emulsion without coarse particles was obtained in Comparative Example 8. When the mixture was kept at 30°C for 16 hours, the entire mixture turned into a gel, and even when the temperature was returned to 30°C, it remained a gel-like substance, and its stability was extremely poor. Furthermore, the obtained film easily re-emulsifies when water droplets are applied and rubbed lightly with a finger, and the film has no water resistance at all, and the modified film used in the present invention
There was no way that it would be as effective as when using PVA.

[Table] A test was conducted to see if the film could be re-emulsified by rubbing.
Note 6) Polyoxyethylene nonyl phenyl ether 10
Part combination

Claims (1)

[Scope of Claims] 1 (A) a vinyl ether having an alkyl group having 4 or more carbon atoms (B) a monomer represented by the general formula (), In the above formula, R ₁ ; hydrogen or lower alkyl group R ₂ ; alkyl groups R ₃ , R ₄ , R ₅ ; hydrogen or alkyl group M; one equivalent of hydrogen or cation (C) vinyl acetate; An emulsifying and dispersing agent that is made of modified polyvinyl alcohol obtained by saponifying a copolymer and is capable of emulsifying and dispersing a lipophilic water-insoluble substance in an aqueous medium. 2 (B) component is R ₁ , R ₄ , R ₅ in general formula ()
The emulsifying and dispersing agent according to claim 1, wherein is hydrogen, and R ₂ and R ₃ are methyl groups.